Iceland's fans celebrate their team's victory against Kosovo, following the World Cup Group I qualifying soccer match between Iceland and Kosovo in Reykjavik, Iceland, Monday Oct. 9, 2017. (AP Photo/Brynjar Gunnarsson).

United States' Christian Pulisic, right, is comforted by a member of the team staff after the U.S. lost to Trinidad and Tobago in their World Cup qualifying match, at Ato Boldon Stadium in Couva, Trinidad and Tobago, Tuesday, Oct. 10, 2017. (AP Photo/Rebecca Blackwell)

Panama's Roman Torres celebrates his goal against Costa Rica and his team's 2-1 victory, qualifying his team for the 2018 Russia World Cup in Panama City, Tuesday, Oct. 10, 2017. It's the first time Panama classifies for a World Cup tournament. (AP Photo/Arnulfo Franco)

Portugal's Cristiano Ronaldo, center, celebrates with his teammates at the end of the World Cup Group B qualifying soccer match between Portugal and Switzerland at the Luz stadium in Lisbon, Tuesday, Oct. 10, 2017. (AP Photo/Armando Franca)

A dramatic day of qualifying matches ended with 23 of the 32-team lineup confirmed to play next year in Russia.

Lionel Messi will be there. Cristiano Ronaldo, too. The United States will not, for the first time since 1986.

The remaining nine spots will be decided next month, but the eight top-seeded nations for the Dec. 1 draw in Moscow are now known. There are still four European playoffs, two intercontinental playoffs and three African qualifying groups to be decided.

Here are some things we learned about the next World Cup:

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STAR POWER

Before games kicked off Tuesday, Messi and Ronaldo were not sure of advancing.

It all worked out, to the relief of Argentina, Portugal, FIFA and social media users everywhere. World Cup sponsor Adidas and Nike — who provide the uniforms for Messi and Ronaldo, respectively, on international duty — should also be relieved.

Messi was a savior for Argentina, which likely had to win in the high altitude of Ecuador and trailed in the first minute. The only Argentina player to score in qualifying games this year, Messi's hat trick led the way to a 3-1 win and a spot at the World Cup.

Ronaldo did not add to his 15 goals in qualifying, but Portugal's 2-0 win over Switzerland extended the European champion's winning streak and ensured first place in the group on goal difference.

Not all of the world's best players will be in Russia: Wales forward Gareth Bale, Chile striker Alexis Sanchez and rising American star Christian Pulisic all were eliminated.

Portugal and Argentina went from the fringes to the top-seeded pot of teams as the Nos. 3 and 4 teams in the FIFA rankings.

The top seven-ranked teams — FIFA will confirm the list on Monday — join host Russia in Pot 1. They include top-ranked Germany, the defending champions, Brazil, Belgium, Poland and France.

Russia's ranking, somewhere in the 60s, could be worst in the draw, but is because the host nation has not played high-value competitive qualifying games.

Spain won't be one of the seeded teams, and should be the one to avoid from Pot 2.

FIFA picked a new draw format with seeding pots entirely decided by October's rakings instead of geographical divide. No two teams from the same confederation can be drawn together, except for Europeans. With 14 UEFA members in the draw, FIFA allows a maximum of two in each of the eight groups.

If Serbia lands as an outlier in Pot 4, it could set up the toughest group with either Brazil or Argentina and another European team.

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NEW BOYS

Iceland and Panama are the two World Cup newcomers so far.

Iceland is beloved worldwide after its run to the 2016 European Championship quarterfinals and will be the smallest nation by population — only 330,000 — ever to play at a World Cup. Expect the country's trademark thunderclap salute between players and fans to be admired and copied across the tournament.

Panama's unlikely 2-1 win Tuesday over already-qualified Costa Rica relied on a "goal" that never crossed the line, and an 88th-minute strike from Roman Torres.

Panama took the last direct qualifying place in CONCACAF region, and the United States fell away after a surprising 2-1 loss at Trinidad and Tobago.

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VIBRANT VISITORS

Expect many of Iceland's population to land in Russia, and most will be personal friends of the team.

Iceland's blue and white hordes were a must-see experience at Euro 2016 even before their team eliminated England in the last 16.

For sheer euphoria, Egypt's qualification this week to end a 28-year absence was hard to beat. Egypt already ranks in FIFA's top 10 of nations whose residents have requested tickets to the 64 games in Russia.

Color and noisy good cheer would also be guaranteed if either or both of Ireland or Northern Ireland advance through the European playoffs next month.

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POLITICS

The elimination of Ukraine this week removed a huge potential problem for FIFA.

Teams from Russia and Ukraine have been kept apart for security reasons in competition draws since 2014. It would have struck an awkward tone at the Dec. 1 draw at the State Kremlin Palace.

Syria's exit against Australia on Tuesday also removes the chance of the team's impressive run being used for propaganda by the regime of President Basher Assad, an ally of Russia.

Russian organizers say there will be no repeat of violent clashes involving its fans at the past two European Championships, including against Poland in Warsaw and England in Marseille.

Russia cannot be in a group with top-seeded Poland, but could draw England from Pot 2.

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VIDEO REVIEW

On the field, FIFA still has issues to resolve in refereeing games.

It wasn't up to FIFA to prevent Panama's "ghost" goal, but the technology system will be used at all 12 Russian stadiums for the World Cup.

FIFA is on the clock to decide if referees should get help from video review, however.

Decision-making was slow and often confused at the eight-nation Confederations Cup in Russia this year. Reviews once predicted to last mere seconds stretched to three minutes, and still seemed to get things wrong.

Top-level German and Italian league games are using Video Assistant Referees this season and, again, have provoked anger from team officials.

FIFA's rule-making panel is scheduled to make a decision in March, maybe based more on hope than expectation.